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Thoracentesis

What is thoracentesis?

Thoracentesis is a procedure for removing fluid from the space between the lungs and the inner chest wall. This space is called the chest cavity or pleural space. A needle is used to remove the fluid.

When is it used?

Thoracentesis may be done for 2 reasons:

  • to remove fluid from the chest cavity that is making it hard for you to breathe
  • to get a sample of chest fluid to test for infection or cancer cells.

A buildup of fluid around your lungs may be caused by infection, cancer, liver disease, heart failure, thyroid disease, pancreatitis, a drug reaction, or kidney disease. Lab tests of fluid samples help to find the cause.

How do I prepare for thoracentesis?

You do not need to do anything to prepare for this procedure.

What happens during the procedure?

You will usually sit, sometimes backward on a chair with your arms resting on the back of the chair. The needle site will be cleaned and you will get a shot of painkiller to numb the area. Your provider will insert a needle through the skin, between the ribs, and into the chest cavity. It is important not to cough, breathe deeply, or move suddenly while your provider inserts the needle. A small amount of fluid will be removed for testing. If there is a lot of fluid and it is making it hard for you to breathe, your provider may try to remove as much fluid as possible to improve your breathing. When the procedure is done, your provider will remove the needle and put a bandage on the needle site. The test takes about 10 to 15 minutes.

What happens after the procedure?

After the procedure you may have a chest X-ray to make sure that the lung was not punctured by the needle. The X-ray will also show how much fluid is left in the chest.

What are the benefits of this procedure?

Thoracentesis helps your provider diagnose an infection or tumor in the chest. Another benefit is that it will be easier for you to breathe after fluid is removed.

What are the risks of this procedure?

The main but uncommon risk is accidental puncturing of the lung when the needle is inserted or moved. This is called a collapsed lung or pneumothorax. When it happens, air leaks from the lungs and gets trapped in the chest cavity. A small leak is usually not a problem. The air is absorbed by the body over a few hours or a few days. The only treatment for a small leak may be follow-up chest X-rays to confirm that the air is being absorbed. A larger leak may require treatment to remove air from the chest and allow normal breathing. Other, uncommon side effects are infection or bleeding.


Also, if a lot of fluid was removed, more fluid may again build up in the lungs, depending on the cause of the fluid.

When should I call my healthcare provider?

Call your provider right away if:

  • You are having trouble breathing.
  • You have pain in your chest, shoulder, or upper back.

Call during office hours if:

  • You have questions about your results.
  • You have questions about when to schedule your follow-up visit.

Disclaimer: This content is reviewed periodically and is subject to change as new health information becomes available. The information provided is intended to be informative and educational and is not a replacement for professional medical evaluation, advice, diagnosis or treatment by a healthcare professional.


HIA File resp4818.htm Release 13/2010

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